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Manufacturers are adamant hybrid powertrains are the wave of the future. So why aren’t there more of them on the road?

By Jack Roberts

It was almost 10 years ago when I saw my first medium-duty hybrid-drive truck. It was a Class 5 International tricked out as a bucket truck. The technology was pretty neat, although it seemed limited at the time. There were some fuel economy benefits to the new powertrain. But, at the time, it seemed that hybrids would evolve into a strong niche product: specifically, refuse trucks with their extreme stop-and-start duty cycles or on utility and bucket trucks that could use the system as a powerful, mobile generator to quietly and efficiently work in areas where noise was a factor.

At the time, no one saw $5 a gallon diesel fuel prices on the horizon. In hindsight, it the hybrid truck’s development seems fortuitous. It gave truck manufacturers a readily available weapon to counter alarmingly high fuel prices. And instead of being a niche product, research into hybrid technology is accelerating and there’s a new hybrid model introduced almost every month.

Still, hybrids are relative small fry compared to the huge volumes of conventional gasoline and diesel powertrains sold every year. Why aren’t we seeing more of them on the road?

The answer is that you are, and you will.

“The hybrid truck market has been definitely growing over the past few years due to the increase in availability of these systems,” says Dimitri Kazarinoff, vice president and general manager for Eaton Hybrid Power Systems – a pioneering developer of hybrid technology. “We’ve also been expanding the applicability of hybrids to specific vocations, and that’s helped drive adoption.”

Still, Kazarinoff, says, hybrid numbers remain small in terms of overall penetration. “But,” he notes, “in the past couple of years, we’ve seen a doubling of hybrid volume in North America. And this year will probably do somewhere around a 60 to 75 percent increase on top of that. So we’re seeing significant growth, albeit from a small base.”

That number, according to David Bryant, vocational sales manager, hybrids, for Freightliner Trucks, is currently less than 1 percent of the overall market. And that’s largely due to the higher purchase prices hybrids currently command. “The tipping point with hybrid trucks right now is in the componentry,” Bryant explains. “Due to the relatively low volumes being sold now, component costs remain high. But as we continue to see higher use, the economies of scale will tip and costs will go down.”

Just how much more can hybrids cost? Bryant says in some cases, they can cost as much as 60 percent more than a truck with a conventional powertrain – enough of a premium to make even the most green-minded truck buyer balk. There are incentives in place, however, to help ease get those high initial costs under control. “With certain government incentives, the cost of hybrids can be completely offset, and in some cases, they are cost-neutral with incentives,” Bryant notes.

“The cost of the hybrid system and components and subsequent pricing is a certainly a major inhibitor at the moment,” says Darren Gosbee, director, electric vehicle and hybrid power train product development for Navistar. “The decision to purchase a hybrid truck really comes back to one thing, and that’s payback.”

For Gosbee, that payback can be from government incentives or fuel economy alone. “But regardless,” he says, “those are the factors that determine how quickly the fleet operator can actually get payback on their capital investment.”

“There have been some significant incentives that have dramatically improved the payback for hybrid trucks,” Kazarinoff adds. “California has had a voucher program this year, and there have been IRS tax credits, as well as Clean Cities money coming out of stimulus funds. And depending on the application and the customer, they have different abilities to access some of those incentives.”

As with everything when dealing with trucks, calculating a Return on Investment figure for hybrids is dependent upon application, which in turn determines the fuel economy improvement a hybrid truck gives over a vehicle with a conventional powertrain. “At the moment, because of the relatively low cost of fuel, and the relatively high incremental cost associated with hybrids, that payback is out in the 7- to 9-year timeframe,” Gosbee says.

If and when fuel prices rise again that dynamic begins to change radically. As it is, there is no magic number in terms of fuel prices where hybrids suddenly become irresistible. Instead, Gosbee says, there is a band-width of fuel pricing where hybrid ROI begins to accelerate dramatically. And those fuel prices aren’t that far off. “When you start talking about $4.00 to $4.50 for a gallon of diesel fuel, the payback time on a hybrid purchase starts to shorten significantly,” he says. “And the amount of money you can save rises very quickly as those fuel prices continue to rise.”

“ROI varies a lot by application or vocation and specific duty cycle,” Kazarinoff adds. “In some applications, there definitely is an attractive ROI, just on a pure brake and fuel savings basis.”

In talks with hybrid fleet owners and drivers, Kazarinoff says noise is often cited as the biggest advantage to operating a hybrid utility truck in urban surroundings. Lower emissions, increased brake and engine component life and the simple marketing cache of running a “green” business can all be factors in determining ROI as well. “It’s a variety of things, some of which go beyond the very simple, ‘Just how much fuel am I saving?’ kind of calculation,” Kazarinoff adds. “And for some of our customers, clearly at this point, there’s been an investment they’ve made based on the improved environmental reputation it brings with them.”

The next generation

Truck manufacturers say as hybrid systems become more commonplace in the future, demands for increased electric performance will rise accordingly. And they are already researching and testing the next generation of hybrid drivetrains.

“A parallel system is what you commonly see today in the automotive world as well as the truck world,” Douglas says. “This is essentially an electric motor/generator running parallel to the primary drivetrain, usually a diesel engine.”

In contrast, Douglas explains, a series system features a much higher degree of hybridized systems on the vehicle – systems that are no longer wholly dependent upon the diesel engine for operation. “In Kenworth’s case, with series hybrid systems, we’re trying to electrify systems so we get away from launch-assist and try to hybridize as many systems in the truck as possible.”

“There’s limited amount of capability right now to do what I would call electric-only operation,” Kazarinoff says. “That’s because you still need power brakes, power steering, air conditioning – all those systems on a conventional vehicle are still being driven as mechanical accessories off of the engine. So you currently have issues in terms of shutting the engine off and continuing to operate those systems.”

To address these shortcomings, Kazarinoff says Eaton is working on a plug-in electric hybrid program for utility trucks that will electrify accessories such as power steering and brakes, and enable limited amounts of electric-only operation. “Again, that is another avenue to enhance the efficiency and functionality of the system,” he says. “Because even at idle or light load conditions, diesel engines run relatively inefficiently. So if we can better restrict the diesel engine to operate in a region – a range of operation where it is more efficient, that’s going to unlock a lot more value for customers.”

“The opportunity for hybrids to have a more significant impact on the marketplace comes into play when a retrofit system can be installed on existing vehicles with minimal effort,” says Ken Gillies, truck operations manager, GE Capital Fleet Services. “If a system uses more commonly available components rather than costly specialty parts can be developed, it would be extremely beneficial. EMD Technologies currently offers a solution of this type that shows potential to convert to a hybrid drive and yet enable a ROI of two to three years.”

Gosbee says that looking even farther ahead, potential government fuel economy legislation will drive manufacturers to focus on ways to maximize energy recovery. “Not just energy recovery from a stop-start cycle like we have now,” he says. “But things like heat recovery from exhaust systems.”

In this scenario, Gosbee says some sort of mechanical or electrical machine that takes heat out of the engine, turns it into energy and then returns it to the drivetrain. “In the case of electrical energy, we can take that exhaust heat and perhaps spin a turbine to create electricity,” he says. “And that electricity could then be put into the driveline as supplemental energy to run any system on the vehicle. The technology is heading in that direction. And I do feel that we will see that kind of hybridization – or perhaps I should say the electrification of certain elements in the drivetrain – become apparent in Class 8 trucks.”

It’s clear hybrids will become increasingly commonplace. And despite all the enhancements in improvements on the drawing board now, OEMs stress that hybrid trucks in their current incarnation are a viable option for businesses today. “We’re not just talking about experimental prototypes anymore,” Kazarinoff notes. “We’ve got more than 55 million miles of customer use on hybrid electric systems and thousands of them in operation all over the world in many different applications. So in that sense, it’s really a proven, available now, reliable product.” EW